Experience Exchange Sever

January 28, 2010

What do you know about Deframentation – Exchange server

Filed under: Database, Exchange 2003 — vijayarelangovan @ 9:01 pm
  • Online deframentation – Does not reduce the physical size of the database · Offline Defragmentation – Reduces the physical size of the database ·
  • Online defragmentation runs for 15 minutes at the end of the database maintenance cycle (assuming that a task has completed).
  • By default, maintenance runs from midnight to 4 a.m.
  • When you run eseutil /d against a database to defragment it, the streaming file associated with the database is automatically defragmented. If you do not want the streaming file to be defragmented, include the /i option.
  • Time that the defragmentation will take will depend on the amount of white space in the database, as well as the size of the transactions recorded in the database, and your hardware specifications.

There are 11 task that is perfromed by online maintenance along with the defragmentation. They are

  1. Purge the indexes on the mailbox and public folder stores.
  2. Perform tombstone maintenance on mailboxes and public folders.
  3. Remove expired messages from the dumpster for the mailbox and public folder stores.
  4. Remove expired messages from public folders.
  5. Remove deleted public folders with tombstones over 180 days old.
  6. Clean up message conflicts within public folders.
  7. Update server version information on public folders.
  8. Check for and remove duplicate site folders on public folder stores.
  9. Clean up deleted mailboxes on mailbox stores.
  10. Check the message table for orphaned messages (messages with a reference count of 0).
  11. Perform an online defragmentation of the store.

January 21, 2010

gatewayProxy Vs GatewayProxy – E2K3

Filed under: Exchange 2003 — vijayarelangovan @ 9:16 pm

1. Difference between ‘gatewayProxy’ attribute on the Recipient Update Service object and ‘GatewayProxy’ attribute on the Recipient Policies object.

  • gatewayProxy is populated when the policy is applied and Recipient Update Service begins processing all the users who match the filter on the applied policy.
  • If the Recipient Update Service finishes processing the users successfully, it clears the corresponding entries from the gatewayProxy
  • If you clear the gatewayProxy attribute on the Recipient Update Service will not do anything, just helps the RUS to update the address to the object.

***If you clear the GatewayProxy attribute on the Recipient Policies will not do anything, it just stops the email flow. *** Do not try on the customer’s server.

2. Why the gatewayProxy on the Recipient Update Service is not cleared after the policy is applied?????

The possible reasons are:

  • When the Recipient Update Service or the Mad.exe process is killed or stops responding,  gatewayProxy attribute is not cleared because it has not completed processing the objects that apply to the policy.  Even when you restart the Recipient Update Service or the Microsoft Exchange System Attendant service(mad.exe) does not remove or clear the gatewayProxy attribute.
  • When Exchange System Manager and The System attendant (mad.exe) tries to access the gatewayProxy attribute at the same time

Link State Information – E2K3

Filed under: Exchange 2003, Mail flow — vijayarelangovan @ 8:57 pm

LINK STATE TABLE

  • Link state table contains the following information

o   List of all Connectors      -> Name

o   Link status of the connectors      ->            Up/Down

o   Link cost of the connectors          ->            Value

  • Link state table information will be available with the Routing group master
  • The Routing Group Master will be communicating with the other exchange server to update the LST through the TCP port 691
  • The Routing Group Master will update the LST to the bridgehead server and bridgehead server sends the updated LST to the other bridgehead server in other routing group through TCP Port 25

Mail is not reaching the Inbox

Filed under: Exchange 2003, Mail flow — vijayarelangovan @ 8:00 am

In recent past, we had few cases with  “Incoming emails to the server does not reach the users inbox” problem.  In all the instances we were able to fix the problem with solution provided in this email.

Issue : Incoming emails to the server does not reach the users inbox

Solution : Follow the steps if the conditions are satisfied

Condition 1 :  Do is message tracking

Condition 2 :  If the email either in the Deleted items or Recover deleted items (Dumpster)

Step 1 : download and run the mfcmapi.exe

Step 2 : Follow these steps to delete the junk email rule

1.      Click Mfcmapi.exe

2.      Click Session -> click Logon And Display Store Table

3.      Choose the Profile Name -> click ok

4.      Click MDB -> Get Mailbox Table

5.      Double click on the user Mailbox

6.      Expand Top of information Store table

7.      Right Click on the inbox -> Open Assosicated Mailbox

8.      Right click on the Junk email rule ->Delete messages

Step 3 : Close the outlook of the user and reopen it again

Reason : The emails are routed to the Dumpster or the Deleted items due to the corrupted junk email rule installed by the IMF.

January 20, 2010

SMTP vs Memory

Filed under: Exchange 2003 — vijayarelangovan @ 10:34 pm

  • SMTP gateway servers use memory primarily for maintaining connections and keeping track of vital information about messages in the queues.
  • The memory used to store message properties on queued e-mail can be significant.
  • SMTP stores messages in the queue in two states:

1. opened (that it, it keeps a handle open) or

2. closed (that is, it closes the handle).

  • The maximum number of messages that an SMTP gateway queues before refusing new messages is 90,000.
  • SMTP can keep 1,000 messages in the queue open at any particular time, closing old messages as new ones arrive.
  • An open message in the queue consumes approximately 10 KB of memory in the Inetinfo process, and a closed message consumes approximately 4 KB of memory in the Inetinfo process.
  • The maximum number of messages that an SMTP gateway queues before refusing new messages is 90,000.
  • A simple calculation that explains this,

1,000 open messages = 10 MB of Inetinfo memory

1,000 open messages + 20,000 closed messages = 80 MB of Inetinfo memory

1,000 open messages + 89,000 closed messages = 366 MB of Inetinfo memory

Traffics:

  • Low-traffic SMTP gateway servers can perform adequately with 256 MB of RAM.
  • In high-traffic data centers, where large queues are common and large distribution lists are expanded, at least 512 MB of RAM is preferred.
  • Generally, an SMTP gateway server does not benefit by having more than 1 GB of memory.

Which means that at any given point of time, any Exchange server with basic configuration is capable of handling emails of any size.

Slow Mail flow?

Filed under: Exchange 2003, Mail flow — vijayarelangovan @ 10:29 pm

Would the Disk bottleneck affect the mail flow?

As well all know, yes that will “affect the slow or affect” the mail flow

Reason:

Every message that is received by an SMTP gateway is saved to a disk.

  • With a default message size of 50 KB, about 7 to 8 disk writes occur for each message processed by the SMTP gateway.
  • This behavior is expected. Generally, SMTP performs 7 disk writes for every message queued that is smaller than 32 KB.
  • An SMTP gateway’s write buffer is 32 KB. Therefore, messages that are larger than 32 KB require an additional disk write for every 32 KB.

For example, a 100-KB message requires 10 disk writes to save the message in the queue.than 1 GB of memory.

it is good to run EXTRA to check the disk bottleneck and blame the “Third party” with a proof J

X:400 NDR Error when sending emails to E2K7 Server

Filed under: Exchange 2003, Mail flow — vijayarelangovan @ 10:27 pm

I’ve recently come across a problem where, For Exchange 2003 and 2007 co-existence environment, When an mail-enabled object is created, the x:400 address will not be stamped.

This would result in an NDR’s with the recipient name “BsB57FD40C9308F7479BF159E9F227E5DD_

cn=E5D7F3DC762455418BB3D96C1B7C13BC@domain.edu

Reason:

This would happen because of mission X:400 address

Fix:

  • The Exchange 2003 RUS is responsible to update the object attributes in a co-exist Environment.
  • The Recipient Update Service has three System Policies that are installed by default when you install Exchange 2003. They are “Mail Enable Recipient”, “Mailbox Enable User” and “Hidden DL membership”.
  • If the recipient update service identifies than a new entry was added (or modified), and it does have the mailNickname to be considered mail-enabled.  Therefore, by default, the purportedsearch attribute should be below:

(|(&(objectCategory=person)(objectClass=user)(mailnickname=*)

(targetAddress=*))(&(objectCategory=person)(objectClass=contact)

(mailnickname=*)(targetAddress=*))(&(objectCategory=group)

(mailnickname=*))(&(objectCategory=publicFolder)(mailnickname=*)))

  • You can locate the “Mail Enable Recipient” object by using Adsiedit.msc tool:

CN=Mail Enable Recipient, CN=System Policies, CN=ORG_NAME, CN=Microsoft Exchange, CN=Services, CN=Configuration, DC=DOMAIN_NAME,DC=com

  • The user, contact and public folder object which have mailnickname and targetaddress (not for public folder) attributes.

No-Listing

Filed under: DNS, Exchange 2003, Exchange 2007 — vijayarelangovan @ 9:12 pm

I found interesting concept somewhere in the web  to  reduce the spam that comes in to the organization.

As we all know mx record plays a major role for receiving email.  And it is also the entry point for the spam to enter into the organization.

“Nolisting” is a concept of creating more than two mx records, and setting the primary mx record to “nowhere”(ie 0.0.0.0).

As per RFC-(forgot the number), a genuine email from a genuine sender should try the secondary if the primary is not available or invalid.

Spammers won’t strain much to try to resend the email to the secondary mx record.  This way you can reduce the spam coming into your organization

January 15, 2010

My First Blog

Filed under: Exchange 2003 — vijayarelangovan @ 10:51 pm

I’ve started this blog to share my experience when i work with exchange server.  I really appreciate all your comments and feedbacks.

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